Effect of ultrasonic vibration treatment on microstructure evolution and mechanical properties of Cu-TiB2 composites

Abstract

The distribution of second-phase particles is crucial to the mechanical properties of particulate reinforced copper matrix composites (PRCMCs). Ultrasonic vibration treatment (UVT), as an effective technique to disperse second-phase particles in metallic melts, has been extended to treat PRCMCs using a SiAlON sonotrode. In this study, systematic experiments have been conducted to explore the effect of UVT on the microstructures and mechanical properties of in situ Cu-TiB2 composites. The results indicated an optimal duration of UVT for 3 min, featured by an improved distribution of TiB2 particles and superior mechanical properties of the as-cast composite. The ultimate tensile strength, yield strength, and elongation exhibited significant increases of 15.7%, 18.1%, and 36.1%, respectively, compared to the as-cast Cu-TiB2 composite without UVT. Furthermore, these experimental composites were subject to rolling deformation. The results once again demonstrated that the as-rolled Cu-TiB2 composite, treated with UVT for 3 min, stood out as the best. The ultimate tensile strength, yield strength, and elongation of the as-rolled Cu-TiB2 composite were 459 MPa, 422 MPa, and 7.0%, respectively. Based on the microstructural observation, the mechanism underlying the UVT-induced enhancement of mechanical properties was discussed in terms of the non-linear effects of ultrasound cavitation on liquid metals. This work can provide a strategy for producing high-performance PRCMCs through UVT.